Multi-technology processes for (indoor) positioning attempt to estimate a position of a device using measurement data from multiple, independent sources, e.g., Wi-Fi, GNSS, Bluetooth® wireless technology, sensors (e.g., MEMS sensors such as accelerometers, gyroscopes, magnetometers, and so on), and assistance data relating to a local environment, e.g., access point or cell tower database, street map, a building floorplan, etc. However, error biases from different sources are often ignored. For example, successive Wi-Fi/GNSS/cellular measurement sets are treated as independent; bias in PDR heading or step length is often ignored; and each successive use of a transmitter position estimate from a database is treated as independent. That is, errors between one set of data and the next are usually treated as uncorrelated. This can lead to large errors in the final position estimate.